In a thermal ink jet printhead, printhead heater chips carry the heating elements that provide heat to the ink, thereby creating the bubble of ink that ultimately prints on a receiving surface, such as paper. During the manufacturing of ink jet printheads, printhead heater chips can be damaged. Faults, such as cracks and fractures, many of which are not readily detectable, can be introduced. Minor faults can further propagate during shipping and operation, causing the printheads to fail prematurely, resulting in customer dissatisfaction.
It is desirable to have a method of detecting faults that is relatively simple and inexpensive. Preferably, such a method can be incorporated in the manufacturing cycle such that testing for faults can occur before manufacture of the printhead is completed.
The method of the present invention provides for an easy and low cost method of testing for faults in printhead heater chips. The method utilizes the incorporation of a simple resistor adjacent to any edge of the heater chip where a fault may occur. It does not require the addition of complicated electronic components to the printhead heater chip.